<!DOCTYPE html
    PUBLIC "-//W3C//h2D XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/h2D/xhtml1-transitional.h2d">
<html xmlns="http://www.w3.org/1999/xhtml">

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>JavaScript简易日历</title>
    <style type="text/css">
        * {
            padding: 0;
            margin: 0;
        }

        li {
            list-style: none;
        }

        body {
            background: #f6f9fc;
            font-family: arial;
        }

        .calendar {
            width: 210px;
            margin: 0 auto;
            padding: 10px 10px 20px 20px;
            background: #eae9e9;
        }

        .calendar ul {
            width: 210px;
            overflow: hidden;
            padding-bottom: 10px;
        }

        .calendar li {
            float: left;
            width: 58px;
            height: 54px;
            margin: 10px 10px 0 0;
            border: 1px solid #fff;
            background: #424242;
            color: #fff;
            text-align: center;
            cursor: pointer;
        }

        .calendar li h2 {
            font-size: 20px;
            padding-top: 5px;
        }

        .calendar li p {
            font-size: 14px;
        }

        .calendar .active {
            border: 1px solid #424242;
            background: #fff;
            color: #e84a7e;
        }

        .calendar .active p {
            font-weight: bold;
        }

        .calendar .text {
            width: 178px;
            padding: 0 10px 10px;
            border: 1px solid #fff;
            padding-top: 10px;
            background: #f1f1f1;
            color: #555;
        }

        .calendar .text h2 {
            font-size: 14px;
            margin-bottom: 10px;
        }

        .calendar .text p {
            font-size: 12px;
            line-height: 18px;
        }
    </style>
    <script type="text/javascript">
        window.onload = function () {
            arr = ['快过年了，大家可以商量着去哪玩吧～', '二月份过年出去浪', '大家好好学习吧222222333~~~', '大家好好学习吧222444222~~~', '大家好好学习555吧222222~~~', '大家好好学习吧666222222~~~', '大家好好学习吧227772222~~~', '大家好好学习吧28888822222~~~', '大家好好学习吧99999222222~~~', '大家好好学习10000000吧222222~~~', '大家好好学习吧111111222222~~~', '大家好好学习吧22222200000000000~~~']
            var h2 = document.querySelector("#txt h2") //几月活动
            var pele = document.querySelector("#txt p");//活动内容
            var lis = document.querySelectorAll("#ul li")
            for (var i = 0; i < lis.length; i++) {
                lis[i].index = i;//绑定下标
                lis[i].onclick = function () {
                    for (var j = 0; j < lis.length; j++) {
                        lis[j].className = ""
                    }
                    this.className = "active"
                    // 显示几月活动
                    h2.innerHTML = (this.index + 1) + "月活动";
                    // 显示活动内容
                    pele.innerHTML = arr[this.index]
                }
            }
        }
    </script>
</head>

<body>

    <div id="tab" class="calendar">

        <ul id="ul">
            <li class="active">
                <h2>1</h2>
                <p>JAN</p>
            </li>
            <li>
                <h2>2</h2>
                <p>FER</p>
            </li>
            <li>
                <h2>3</h2>
                <p>MAR</p>
            </li>
            <li>
                <h2>4</h2>
                <p>APR</p>
            </li>
            <li>
                <h2>5</h2>
                <p>MAY</p>
            </li>
            <li>
                <h2>6</h2>
                <p>JUN</p>
            </li>
            <li>
                <h2>7</h2>
                <p>JUL</p>
            </li>
            <li>
                <h2>8</h2>
                <p>AUG</p>
            </li>
            <li>
                <h2>9</h2>
                <p>SEP</p>
            </li>
            <li>
                <h2>10</h2>
                <p>OCT</p>
            </li>
            <li>
                <h2>11</h2>
                <p>NOV</p>
            </li>
            <li>
                <h2>12</h2>
                <p>DEC</p>
            </li>
        </ul>

        <div class="text" id="txt">
            <h2>1月活动</h2>
            <p>快过年了，大家可以商量着去哪玩吧～</p>
        </div>

    </div>

</body>

</html>